The invention addresses in particular the issue of electrical consumption, and therefore the power efficiency of the radiofrequency transmission modules, in particular within the framework of the abovementioned H-V-UHF radio stations.
Typically, a transmission module comprises a logic circuit whose function is notably to transmit the samples describing the baseband digital signal to a digital-analogue converter or DAC. The analogue baseband signal is then transposed to an RF frequency using an IQ modulator, given the integration of digital modulations in software radios. The RF signal is then filtered and amplified in order to optimize the linearity and the gain chain. Finally, for applications involving signals of high levels, the RF signal is amplified by using power stages, such as preamplifiers and power amplifiers, depending on the power wanted at the output of the antenna.
This type of setup presents a number of drawbacks, including:                a low efficiency of the baseband amplification chain, many watts being lost;        a complexity of the baseband amplification chain with multiple band filters, each occupying a not-inconsiderable volume;        a very low efficiency of the communications station for modulations with non-constant envelope, which greatly limits the average power of the station, and therefore its range.        
These problems are notably due to the fact that, currently, two radio stations are needed to cover the HF-VHF-UHF needs, one station being dedicated to transmission in the HF band and the other station being dedicated to transmission in the VHF and UHF bands.
Given these conditions, the following needs can be listed for the RF transmission modules:                saving in terms of surface area and volume occupied, reduced production cost;        improved power efficiency over each HF, VHF and UHF sub band compared to that of the current RF stations.        